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Wysocki" Cc: Bjorn Helgaas , Bjorn Helgaas , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Linux PM , Mika Westerberg References: <20220204233219.GA228585@bhelgaas> <8f89131c-41a2-02e4-1427-8a5b1704e0ea@nvidia.com> <469a9db5-9868-cb17-dd5c-96ef29193fda@nvidia.com> <2632919.mvXUDI8C0e@kreacher> From: Abhishek Sahu X-Nvconfidentiality: public In-Reply-To: <2632919.mvXUDI8C0e@kreacher> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ClientProxiedBy: MAXPR01CA0115.INDPRD01.PROD.OUTLOOK.COM (2603:1096:a00:5d::33) To BL1PR12MB5304.namprd12.prod.outlook.com (2603:10b6:208:314::13) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 25c170a3-5fa1-4390-e13a-08da178ee814 X-MS-TrafficTypeDiagnostic: MN2PR12MB3277:EE_ X-Microsoft-Antispam-PRVS: X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:BL1PR12MB5304.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230001)(4636009)(366004)(2906002)(38100700002)(5660300002)(4326008)(66556008)(66476007)(316002)(8676002)(66946007)(31686004)(36756003)(8936002)(31696002)(186003)(966005)(6486002)(86362001)(54906003)(2616005)(6916009)(83380400001)(6512007)(26005)(6666004)(55236004)(53546011)(6506007)(45080400002)(508600001)(43740500002)(45980500001);DIR:OUT;SFP:1101; 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Wysocki wrote: > On Tuesday, April 5, 2022 6:36:34 PM CEST Abhishek Sahu wrote: >> On 2/8/2022 4:00 PM, Abhishek Sahu wrote: >>> On 2/8/2022 12:28 AM, Rafael J. Wysocki wrote: >>>> On Saturday, February 5, 2022 12:32:19 AM CET Bjorn Helgaas wrote: >>>>> [+cc Rafael, hoping for your review :) >>>> >>>> +Mika >>>> >>>>> Wonder if we should add something like this to MAINTAINERS so you get >>>>> cc'd on power-related things: >>>>> >>>>> diff --git a/MAINTAINERS b/MAINTAINERS >>>>> index ea3e6c914384..3d9a211cad5d 100644 >>>>> --- a/MAINTAINERS >>>>> +++ b/MAINTAINERS >>>>> @@ -15422,6 +15422,7 @@ F: include/linux/pm.h >>>>> F: include/linux/pm_* >>>>> F: include/linux/powercap.h >>>>> F: kernel/configs/nopm.config >>>>> +K: pci_[a-z_]*power[a-z_]*\( >>>> >>>> It seems so, but generally PM patches should be CCed to linux-pm anyway. >>>> >>>>> >>>>> DYNAMIC THERMAL POWER MANAGEMENT (DTPM) >>>>> M: Daniel Lezcano >>>>> ] >>>>> >>>>> On Mon, Jan 24, 2022 at 05:51:07PM +0530, Abhishek Sahu wrote: >>>>>> Consider the following sequence during PCI device runtime >>>>>> suspend/resume: >>>>>> >>>>>> 1. PCI device goes into runtime suspended state. The PCI state >>>>>> will be changed to PCI_D0 and then pci_platform_power_transition() >>>>>> will be called which changes the ACPI state to ACPI_STATE_D3_HOT. >>>> >>>> You mean PCI_D3hot I suppose? >>>> >>> >>> Yes. It should be PCI_D3hot here. >>> >>>>>> 2. Parent bridge goes into runtime suspended state. If parent >>>>>> bridge supports D3cold, then it will change the power state of all its >>>>>> children to D3cold state and the power will be removed. >>>>>> >>>>>> 3. During wake-up time, the bridge will be runtime resumed first >>>>>> and pci_power_up() will be called for the bridge. Now, the power >>>>>> supply will be resumed. >>>>>> >>>>>> 4. pci_resume_bus() will be called which will internally invoke >>>>>> pci_restore_standard_config(). pci_update_current_state() >>>>>> will read PCI_PM_CTRL register and the current_state will be >>>>>> updated to D0. >>>>>> >>>>>> In the above process, at step 4, the ACPI device state will still be >>>>>> ACPI_STATE_D3_HOT since pci_platform_power_transition() is not being >>>>>> invoked. >>>> >>>> I'm not quite following. >>>> >>>> I'm assuming that this description applies to the endpoint device that was >>>> previously put into D3_hot. >>>> >>> >>> Yes. This is applicable for endpoint devices which was previously put >>> into D3hot. >>> >>>> Since its current state is D3_hot, it is not D0 (in particular) and the >>>> pci_set_power_state() in pci_restore_standard_config() should put int into >>>> D0 proper, including the platform firmware part. >>>> >>> >>> The pci_restore_standard_config() for endpoint devices are being called >>> internally during wake-up of upstream bridge. >>> >>> pci_power_up(struct pci_dev *dev) >>> { >>> ... >>> if (dev->runtime_d3cold) { >>> /* >>> * When powering on a bridge from D3cold, the whole hierarchy >>> * may be powered on into D0uninitialized state, resume them to >>> * give them a chance to suspend again >>> */ >>> pci_resume_bus(dev->subordinate); >>> } >>> ... >>> } >>> >>> For the upstream bridge, the above code will trigger the wake-up of >>> endpoint devices and then following code will be executed for the >>> endpoint devices: >>> >>> pci_update_current_state(struct pci_dev *dev, pci_power_t state) >>> { >>> if (platform_pci_get_power_state(dev) == PCI_D3cold || >>> !pci_device_is_present(dev)) { >>> dev->current_state = PCI_D3cold; >>> } else if (dev->pm_cap) { >>> u16 pmcsr; >>> >>> pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr); >>> dev->current_state = (pmcsr & PCI_PM_CTRL_STATE_MASK); >>> } else { >>> dev->current_state = state; >>> } >>> } >>> >>> In the above code, the current_state will be set to D0 for the >>> endpoint devices since it will go into second block where >>> it will read the PM_CTRL register. >>> >>>>>> We need call the pci_platform_power_transition() with state >>>>>> D0 to change the ACPI state to ACPI_STATE_D0. >>>>>> >>>>>> This patch calls pci_power_up() if current power state is D0 inside >>>>>> pci_restore_standard_config(). This pci_power_up() will change the >>>>>> ACPI state to ACPI_STATE_D0. >>>>>> >>>>>> Following are the steps to confirm: >>>>>> >>>>>> Enable the debug prints in acpi_pci_set_power_state() >>>>>> >>>>>> 0000:01:00.0 is PCI device and 0000:00:01.0 is parent bridge device >>>>>> >>>>>> Before: >>>>>> >>>>>> 0000:01:00.0: power state changed by ACPI to D3hot >>>>>> 0000:00:01.0: power state changed by ACPI to D3cold >>>>>> 0000:00:01.0: power state changed by ACPI to D0 >>>>>> >>>>>> After: >>>>>> >>>>>> 0000:01:00.0: power state changed by ACPI to D3hot >>>>>> 0000:00:01.0: power state changed by ACPI to D3cold >>>>>> 0000:00:01.0: power state changed by ACPI to D0 >>>>>> 0000:01:00.0: power state changed by ACPI to D0 >>>>>> >>>>>> So with this patch, the PCI device ACPI state is also being >>>>>> changed to D0. >>>>>> >>>>>> Signed-off-by: Abhishek Sahu >>>>>> --- >>>>>> drivers/pci/pci-driver.c | 14 +++++++++++--- >>>>>> 1 file changed, 11 insertions(+), 3 deletions(-) >>>>>> >>>>>> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c >>>>>> index 588588cfda48..64e0cca12f16 100644 >>>>>> --- a/drivers/pci/pci-driver.c >>>>>> +++ b/drivers/pci/pci-driver.c >>>>>> @@ -521,14 +521,22 @@ static void pci_device_shutdown(struct device *dev) >>>>>> */ >>>>>> static int pci_restore_standard_config(struct pci_dev *pci_dev) >>>>>> { >>>>>> + int error = 0; >>>>>> pci_update_current_state(pci_dev, PCI_UNKNOWN); >>>>>> >>>>>> if (pci_dev->current_state != PCI_D0) { >>>>>> - int error = pci_set_power_state(pci_dev, PCI_D0); >>>>>> - if (error) >>>>>> - return error; >>>>>> + error = pci_set_power_state(pci_dev, PCI_D0); >>>>>> + } else { >>>>>> + /* >>>>>> + * The platform power state can still be non-D0, so this is >>>>>> + * required to change the platform power state to D0. >>>>>> + */ >>>> >>>> This really isn't expected to happen. >>>> >>>> If the device's power state has been changed to D3hot by ACPI, it is not in D0. >>>> >>>> It looks like the state tracking is not working here. >>>> >>> >>> The state setting to D0 is happening due to the current logic present in >>> pci_update_current_state(). If we can fix the logic in >>> pci_update_current_state() to detect this condition and return state D3hot, >>> then it should also fix the issue. >>> >>> Thanks, >>> Abhishek >>> >> >> Hi Rafael/Mika, >> >> Could you please help regarding the correct way to fix this issue. >> I can update the patch accordingly. > > I think you can try one of the patches posted recently: > > https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatchwork.kernel.org%2Fproject%2Flinux-pm%2Fpatch%2F3623886.MHq7AAxBmi%40kreacher%2F&data=04%7C01%7Cabhsahu%40nvidia.com%7Cae4c8574f5a44973514a08da172471d6%7C43083d15727340c1b7db39efd9ccc17a%7C0%7C0%7C637847743178405297%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=aasJ79EICVnlJQ4EbXA2AtZFW0qnRsMkHEZRI8mnDI8%3D&reserved=0 > > Thanks! > > > Thanks Rafael. I have applied both the changes and still the issue which I mentioned is happening. Following are the prints: 0000:01:00.0: power state changed by ACPI to D3hot 0000:00:01.0: power state changed by ACPI to D3cold 0000:00:01.0: power state changed by ACPI to D0 So ACPI state change is still not happening for PCI endpoint devices. Also, the I checked the code and the pci_power_up() will not be called for endpoint devices. For endpoints, pci_restore_standard_config() will be called first where the current state will come as D0. Thanks, Abhishek